Methods of determining cementation exponent and saturation exponent in porous media from dielectric dispersion data

Patent metadata

Field	Value
Publication number	US-10393641-B2
Application number	US-201514962201-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Oct 30, 2015
Publication date	Aug 27, 2019
Grant date	Aug 27, 2019

Abstract

Methods are provided for determining values of a pore cementation exponent m and/or a saturation exponent n for locations in a formation having similar petrophysical properties. Formation porosity, formation water saturation, and an apparent cementation exponent mn are obtained for the locations and their values are utilized to find the exponents. In one embodiment, the apparent cementation exponent and the formation water saturation are obtained from a dielectric logging tool.

First claim

What is claimed is:

1. A method for determining values of at least one parameter of a formation to generate an improved virgin zone water saturation, the method comprising:
performing a dielectric measurement of the formation to obtain dielectric data using a dielectric tool included within a wellbore logging tool;
performing a nuclear magnetic resonance (NMR) measurement of the formation to obtain NMR data using an NMR tool included within the wellbore logging tool;
performing a measurement of the formation to obtain formation data using a neutron porosity tool included within the wellbore logging tool;
determining formation porosity ϕ, formation water saturation S w , and apparent cementation exponent m n for a plurality of locations in the formation having similar petrophysical properties, wherein the apparent cementation exponent is obtained from dielectric data;
determining an estimation of at least one of a pore cementation exponent m and a saturation exponent n from the formation porosity ϕ, the formation water saturation S w , and the apparent cementation exponent m n for the plurality of locations; and
calculating an estimated virgin zone water saturation based upon, at least in part, the estimation of the at least one of the pore cementation exponent m and the saturation exponent n.

2. The method of claim 1 , wherein at least one of the pore cementation exponent m and the saturation exponent n are determined according to:
m n ( i )=( m−n ) a ( i )+ n,

where m n (i) is the estimated m n at depth i of one of the plurality of locations, and

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3. The method of claim 2 , wherein determining at least one of the pore cementation exponent m and the saturation exponent n comprises fitting a line to points on a plot having m n and a(i) as axes, and finding the saturation exponent n as the intersection of the line to where a(i)=0.

4. The method of claim 2 , wherein determining at least one of the pore cementation exponent m and the saturation exponent n comprises fitting a line to points on a plot having m n and a(i) as axes, and finding the pore cementation exponent m as the intersection of the line to where a(i)=1.

5. The method of claim 2 , wherein determining at least one of the pore cementation exponent m and the saturation exponent n comprises finding m and n according to:

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Assignees

• Schlumberger Technology Corp

Inventors

• Donadille Jean-Marc
• Venkataramanan Lalitha
• Gkortsas Vasileios-Marios
• Reeder Blanco Stacy Lynn

Classifications

• G01N27/221

  by investigating the dielectric properties (using microwaves G01N22/00; measuring loss factors or dielectric constants per se G01R27/26) · CPC title

• G01V3/06

  using AC · CPC title

• E21B49/00

  Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells · CPC title

• G01N33/24

  Earth materials (G01N33/42 takes precedence) · CPC title

• G01V3/32

  operating with electron or nuclear magnetic resonance · CPC title